'96 SSE makes about 29 mpg running 75 on a flat interstate but only gets 21 on short trips around town. Wife drives 7 miles one way to work and we make several 15-20 mile trips local driving. I'm happy with 29 Hwy but I would sure like to see my short trip mpg up around 25. Car runs great makes plenty of power and I'm over 40 so it doesn't see WOT very often. How many miles of driving does it normally take to get the PCM to go into closed loop?

Where do I look next?

Recent repairs and tune up parts.....

Plugs and wires 20,000 miles ago
New LIM gaskets
New APN UIM
New PCV valve with new o-rings
New vacuum fittings...NO leaks
New MAP sensor
Cleaned MAF sensor
Cleaned throttle body
Cleaned idle air passage and plunger
New Delphi O2 sensor
New fuel filter
Has K&N 4750 on a rice pipe. (recently cleaned)

I bought the car with 150,000 miles and I have not touched the coils. Can coils get weak and cause a drop in MPG or do they just fail?

I was afraid someone would say that, JR. I was really hoping you could work a little magic for me and find another 4-5 MPG.....

I guess I can always dream

well thing is....you probably have the 3.06 ratio...so those numbers aren't that bad at all. I averaged 24 with my 89 and its 2.84 ratio...but my numbers dropped to 22 with the 93 and its 3.06 ratio. same driving....well...almost..

Not sure what I have for a drive ratio. Tach sits on about 1600-1700 at 60 mph with torque converter locked up. How do I decipher the codes to see which ratio I have?

Thanks

look on your spare tire cover for the rpo codes and then look them up here http://www.bonnevilleclub.com/forum/...e=article&k=13

Thanks JR. Saved me a trip to the garage.

Looking at the city rating of 19 MPG I guess I'm already getting 2 bonus miles and didn't know it.

Yep, you're spot on.

Ask jr's3800 (Don) about my gas mileage paranoia....he knows too well LOL. I average about 17-19 in city, and that'* tons of stop/go/stop/there'* a idiot that can't drive/go involved....